Directions:1. In a large, heavy bottomed skillet or sauté pan, melt butter over low heat. Add onion, and season lightly with salt. Turn heat to medium, and allow onions to cook slowly until very soft, and well browned, about 10-12 minutes.2. While onions are cooking, boil pierogies according to package instructions3. Add sausage to caramelized onions, still cooking on medium heat, and cook until heated through.4. Deglaze the pan with the apple cider (or water) and add spinach.5. Cook spinach until wilted6. Toss in pierogies, season with a few twists of ground pepper, and Enjoy!